Once, thanks to a cardiac ultrasound, I was able to watch my own heart thump away faithfully in real time. The technician said that many patients can’t bear to watch, but I was fascinated and felt privileged to have a glimpse of my own mysterious interior. This sense of curiosity prompted me to read - and the author, Mary Roach, to write – “Gulp: Adventures on the Alimentary Canal.”

Unlike travel writers who explore exotic, faraway places, Roach, an award-winning science writer, takes us on a voyage into the human body to explore the geography of our own innards.

“Yuk! Not reading this one,” I can almost hear you saying, but I can assure you that this meticulously researched and often screamingly funny book makes for an enthralling read. “Gulp” reminds me a little of that old movie, “The Fantastic Voyage,” where a bunch of scientists and physicians are shrunk and injected into the bloodstream of a seriously ill patient – minus the miniature submarine and Raquel Welsh, of course. But truth is often more interesting than fiction, especially in the hands of a gifted writer.

Roach describes the digestive tract as “a railroad flat: a long structure, one room opening into the next, though each with a distinctive look and purpose.” We begin, not with the mouth, but the nose, exploring the role of our sense of smell, without which we would not taste much, as anyone who has ever had a cold can tell you. The first few chapters focus on food and what the mouth does to prepare it for its trip down the alimentary canal.

One of the many pleasures of this book is that Roach finds unusual perspectives from which to look at this process. For example, she turns to a company that manufactures the tasty coatings for animal kibble to show us how our pets’ tastes differ from our own, and she compares the Inuits’ love of organ meats with the general repugnance with which most Americans greet offal. The author also travels the world to track down experts. To learn about the vital role saliva plays, she visits a Dutch spit specialist. Who knew that saliva not only lubricates, but also protects our teeth from bacteria, dilutes the acids we ingest, and begins the process of breaking down food so that we can digest it? Likewise, Roach has conducted a great deal of historical research so that she can fill us in on some of the weird experiments early scientists and physicians performed to try to understand the workings of the digestive tract.

Admittedly, the author seems overly fascinated by the bizarre and often pretty revolting things that happen once we travel below the belt, so to speak. You’ll need a strong stomach to get through the chapter titled “Up Theirs: The Alimentary Canal as Criminal Accomplice,” which concerns, among other things, prisoners smuggling contraband into their cells via what they call the “prison wallet.” I’m sure you get the picture, but you’ll be astounded to discover that among the items brought into jails in this manner are cell phones and chargers, boxes of staples, pencil sharpeners, tobacco, and of course, drugs. Grossamundo. However, the chapters about flatulence are (sorry, I can’t resist) a gas. Roach’s interview with the woman in charge of the Beano Hotline is hysterical.

While, thanks to our cultural conditioning, the “ick factor” of so much of the work of our intestinal tract is huge, Roach makes the subject matter digestible for her readers in two ways. First, her book’s pantry is stocked with interesting facts, answers to questions we’ve probably pondered (like could Jonah really have survived being swallowed by a whale?), and the latest findings about how our bodies process what we eat, protect us, and sometimes rebel. Second, the author has a chatty style and a sly and sparkling sense of humor. Her trademark is the sarcastic one-liner – often her personal response to particularly nasty facts or inane comments. Even her footnotes are eminently readable and often are a source of humor. For example, an asterisk appears after this quote defining a bolus as “Food that is in – as one researcher put it, sounding like a license plate – ‘the swallowable state.’ “ The accompanying footnote reads: “I nominate Rhode Island.”

You might think this book is suitable only for 10-year-old boys who love bathroom jokes, but I’d have to disagree. Granted, you might not want to discuss it at the dinner table, but if you are a curious soul who is the owner of an alimentary canal, and you enjoy excellent writing, “Gulp” should be on your “must read” list.